Operation robots have been applied for some time now in the field of minimal-invasive surgery. These operational robots are provided with at least one, but as a rule with several robot arms, at whose distal ends an endoscopic shank instrument controlled by an operator at a console is arranged in each case. Hereinafter, medical instruments which are used for observing, manipulating or a combination of such functions, for application on or in the body of a living being are to be understood as endoscopic shank instruments. Such an operation robot is known for example from US 2009/0234371 A1.
The shank instruments which are used with this operation robot, at their respective distal shank end comprise an instrument head with a tool which is arranged on this instrument head. Instrument heads which can be angled which is to say angularly bent relative to the shank, are applied in combination with the shank instruments, wherein the tool or a tool carrier which is provided on the instrument head and has a tool, can also be angled with respect to the instrument head. Pull cables which are led through the shank into an instrument housing arranged at the proximal shank end are used for the control of the angling of the instrument head and for the control of the tool or for actuating the instrument head and tool. There, the pull cables are fastened on actuation rollers which are controllably rotatable by way of an actuation motor in each case. The actuation rollers are arranged next to one another in the instrument housing, in a common plane normal to their rotation axis.
The number of the actuation rollers arranged in the instrument housing is determined by the number of degrees of freedom of movement of the instrument head has a significant impact on the size of the instrument housing. The instrument housing is therefore already relatively large with a shank instrument, in whose instrument housing only four actuation rollers are arranged. This size of the instrument housing has been found to be disadvantageous if several of these shank instruments have to be commonly applied in a restricted space, as is the case for example with single port operations, with which the shank instruments are simultaneously led to the field of operation via a common body opening. A large instrument housing has moreover been found to be a hindrance if it is necessary to introduce the shank of these instruments into the body of patient at an as shallow as possible angle to the body surface of this patient.